1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to a full-loading sensing device for sensing loading states of discharged papers.
2. Description of the Related Art
Image forming apparatuses such as facsimiles, laser beam printers, ink-jet printers and copiers function to form an image on a recording medium like a printing paper and output the image-formed recording medium. According to image forming methods, image forming apparatuses may be classified as an indirect type utilizing an indirect medium like a photosensitive body to form an image, and a direct type directly jetting or transferring ink to a recording medium to form an image.
Such an image forming apparatus includes an image forming unit for forming an image on a recording medium supplied from a paper feeding cassette, and an output bin section on which the recording medium having the image formed by the image forming unit is discharged and loaded.
The output bin section is a loading plate having a constant height. Plural sheets of discharged papers are piled up to a predetermined height on the output bin section. The output bin section usually has a loading capacity of 50 to 100 sheets of discharged papers. If the number of discharged papers piled on the output bin section exceeds this loading capacity, newly discharged papers can be interrupted by the discharged papers already piled, thereby causing various printing-related errors. Thus, a full-loading sensing device is demanded, which is capable of determining if the number of discharged papers piled on the output bin section exceeds a predetermined limit (hereinafter referred to as full-loading state), and stopping the image forming apparatus or informing the user of the full-loading state with visual or audible means when the full-loading state is detected.
A conventional full-loading sensing device of the image forming apparatus includes a lever for contacting the discharged papers piled on the output bin section, and a sensor for detecting a full-loading state.
Another feature of such devices, is an openable/closable jam removal cover that is provided near the full-loading sensing device to permit removal of a recording media causing a jam in an arrangement unit or paper discharge unit of the image forming apparatus. A separate jam removal cover sensor is connected to the jam removal cover to sense an open or closed state thereof. If this jam removal cover sensor detects an open state of the jam removal cover, internal power is turned off to stop the operation of the image forming apparatus.
As described above, in the conventional image forming apparatus, the full-loading sensing device and jam removal cover-open sensing device are provided separately, thereby increasing the number of components to be assembled including sensors and sensor brackets, and thereby raising assembly costs.
In addition, in the case where the full-loading sensing device and jam removal cover-open sensing device are used together to form an integrated sensing mechanism, measurement signals produced from these two sensing devices may overlap each other to thereby complicate interpretation of the signals, leading to various operational errors which can cause accidents and lower product reliability.
Accordingly, a need exists for a simpler and effective system and method for sensing and distinguishing both a full-loading state and a jam removal cover-open state of an image forming apparatus.